Study knocks down theory that polar bears can conserve energy while fasting

Scientists knew sea ice is melting and glaciers are dropping, and they knew this would affect polar bears a little because food, of which seal is the major source, will become scarce; but they always thought polar bears would adjust or just adapt to the situation through some physiological mechanism – now, everything is proving them wrong.

Now this hope has been shattered, according to a study by the University of Wyoming: “Our findings suggest that bears are unlikely to avoid deleterious declines in body conditions that are expected with continued ice loss”.

But that theory didn’t seem to hold up when applied on other bears, as this study established that polar bears can not conserve their energy and protective fat, and in fact react like any other mammals when their food is drastically limited.

Because of the ice melt, bears are forced to swim longer distances for their meals. “There still are some fundamental aspects of polar bear biology that we have yet to understand”, Pioneer News reported. Along the norther coast of Alaska and east into Canada, the population centered along the southern Beaufort Sea fell by 40 percent between 2001 and 2010 to around 900 bears.

“They have this ability to temporarily allow the outermost portion of the core of the body to cool off substantially and this protects the innermost vital organs – there was not an expectation of that, it was very surprising”, said Whiteman.

“We found that polar bears appear unable to meaningfully prolong their reliance on stored energy, confirming their vulnerability to lost hunting opportunities on the sea ice”, John Whiteman said. “In reality, we can not do much under the Endangered Species Act to save polar bears“, she says.

To make their findings, the researchers captured over two-dozen polar bears, and outfitted them with temperature loggers. Bears in both habitats reduce their body temperatures and activity levels below those of bears actively hunting and feeding, but not to levels as low as those observed during energy-saving hibernation. Hunting is most successful from April to July when seals use sea ice for rearing pups and molting.

The loss of sea ice in the Arctic, attributed to rising temperatures amid global climate change, has prompted worry about the future of polar bears.

In the months that follow, the ringed seals spend the majority of their time in the water. Increased human activity in the warming Arctic is causing polar bears to expend more energy than usual during the ice-free period, making walking hibernation impossible, according to Sybille Klenzendorf, a senior wildlife specialist with the World Wildlife Fund.

The patterns said researchers were typical of mammals that are food deprived rather than those that are hibernating. “We had one bear in our study who swam 500 miles over nine days”.

And “even though no one had studied polar bear metabolism in the way we tested it in this paper, the idea was perpetuated”.

“This regional heterothermy may represent an adaptation to long-distance swims, although its limits remain unknown”, the researchers said.